Indicator apparatus



June 16, 1925.

c. D. MACGILL INDICATOR APPARATUS Filed Aug. 16, 1921 2 Sheets-Sheet 1 FIG. 7.

FIG. 5.

June 16, 1925.

c. D. MACGILL INDICATOR APPARATUS Filed Aug. 16, 1921 2 Sheets-Sheet 2 FIG. .9. FIG-'8 2 left. Y

Patented June 15,1925

UNITED STATES PATENT, OFFICE.

CHARLES DALBYIPLE HACGILL, OF GLASGOW, SCOTLAND, ABSIGNOB TO BARR AND a STBOUD, mm), 01' GLASGOW, SCOTLAND.

mmcs'ron. mm'ros Application am Au ust 10,1021. lortal No. 492500.

(GRANTED UNDER PROVISION! OF THE ACT 30K 8, 1921, 41 STAT. It, 1318.)

To all whom it may concern:

Be it known that 1, CHARLES DALRmrLn MAOGILL, a subect of the King of Great Britain and Ireland, and of Caxton Street,

5 Anniesland, Glasgow, Scotland, have in is a specification.

This invention relates to indicator apparatus suitable for dealing with indications h which extend from what will be termed zero in a positive and negative sense, of the type comprising carry-over gear, such as is used in counting instruments, which operates to ca over indications from one member to anot er, for instance, for carrying over from a member indicating fractions to one indi- 29 eating units, or fromunits to tens. Apparatus of the type in question is, for example, suitable for indicating angles from zero to 180 port and starboard,.deflections from zero to, say, 49 knots left and right, or

u change of rane from zero to a maximum 0 ening and closing. I

or some purposes 1t is essential that the passage through zero should be uniform with the passage through any of the other 80 indications, for instance, if the drive applied be considered as imparted step-by-step, each step representing an indication of one degree, a uniform assage through zero is as follows :2 rig t, 1 right, 0, 1 left,

An example of apparatus in which this method of uniform progression through zero occurs is described in the specification of British Patent No. 29,422 of 1904, granted to Dawson and Buckham. In construction,

this apparatus may be considered as comprising two separate indicators geared together, as there is one set of drums for positive indications and another set of drums for negative indications, and provision is made whereby in one position of the arts, the zero indication is exhibited on bot sets of drums, and in ositive and negative indications one set 0 the drums is covered and hidden from view while the other set remains exposed.

An example of a paratus in which the zero condition is dea t with b what may be considered to be a sin 1e in icator, in that drums are employed orming only one set,

each marked with positive and ne ative indications, is described in the speci cation of British Patent No. 15256 of 1906, ranted to Barr and Stroud, but in this case t e method of progression through zero is not uniform,

in the sense explained, but is as follows 2 right, 1 right, 0 right, 0 left, 1 left,

2 left.

The object of this invention is to produce 1 hereinafter referred to'generally as a longia tudinal window, carry-over gear, a driven member (which in some cases ma be formed to constitute an indicator mem er), from which step-by-step motion is imparted by the carry-over gear to an indicator member (or series thereof), a shutter-device (hereinafter referred to for vbrevity as a shutter) having apertures hereinafter re ferred to generally as transverse apertures, through which and the longitudinal window strips, hereinafter referred .to generally as transversestrips, of the indicator member (or members) may be viewed, the indicator member (or each of the members) having two such transverse strips, associated with carry-over gear, the construction being such that in one osition of the parts, a portion of each of tlie two transverse strips on the indicator member (or on each of the members) is ex osed to view in alignment, hereinafter w erred to generally as longitudinal through the apertures in the shutter and the longitudinal window, and the carry-over ear is so arranged that when the parts are in that position, it shall operate, by motion imparted to the driven member, to impart to the indicator member (or series thereof) and to the shutter a one step movement 51- multaneously with the initial movement of the driven member in either a forwarder backward sense according to the direction of motion im arted, whereby the shutter operates to hi e from view, in the long1tu dinal alignment aforesaid, the portion of one of the two transverse stri s on the mdicator member (or each of t e members) while leaving a portion of the other transverse strip on the indicator member (or on each of the members) exposed to view.

In construction, the indicator member or members and the shutter may conveniently be mounted to operate about a common axis, for instance, they may be of drum or (1150 character, but it wil be recognized that travelling bands or other equivalents upon which indications are adapted to be placed may be used and actuated in the manner provided for by this invention.

Some examples of construction accord ng to this invention will now be described with reference to the accompanying drawings, in which Figure 1 is an elevation showing portion of an indicator apparatus and longitudmal window through which the indications are seen.

Figure 2 is an elevation of a mechanism with the casing removed showing its parts in the zero indication position.

Figure 3 is a plan showing portions of the mechanism partly in section.

Figure "4 is an end view partly in section and Figure 5 is an end view of parts of the mechanism.

Fi res 6 and 7 are elevations, Fi re fi showing parts of the mechanism in t e position they assume after the zero indication is passed in one direction and Figure 7 the position they assume in the opposite direction.

Figure 8 is a developed view of the surface of the driven member, which in this case constitutes an indicator drum, and Figure 9 is a developed view of the surface of an indicator drum.

Figure 10 is an elevation showing a modification comprising discs.

In the construction illustrated at Figures 1 to 9, A designates a longitudinal win dow formed in the face of the casin of the apparatus through which the in ications to be exhibited are seen in longitudinal alignment. B is a shaft to which rotary motion is adapted to be imparted in a step-by-step manner. C is a drum of lowest denomination fixed to rotate with the shaft B. D and E are drums of higher denomination and F is a shutter all mounted to turn independently about the shaft B- comprising two teeth. The direct driven drum C is rovidcd with two carriers G, G, arraliged iametrically, and the drums D and are rier G. H, H, H, are carry-over sprockets mounted to rotate independently upon a shaft J. K, K, K, are pinions fixed respectively to the sprockets H, H, H, gearing with toothed wheels D, E and F fixed res ively to the drums D, E and shutter With the parts in the position shown at Figures 2, 3 and 4, which is the only position in which the counter shows zero on all drums, one tooth of each carry-over sprocket H, H, meshes centrally between the two teeth of its associated carrier G, and one tooth of the sprocket H meshes centrally between two teeth of one of its associated carriers G, so that motion applied to the shaft B, in either direction, will cause the drum 0, by direct drive from provided each with a single car the shaft B and the drums D, E and shutter F by transmitted drive through the carry-over gear, to be moved one step. The

sitions assumed b the parts after this rst movement has 11 completed are as shown at Fi res 6 and 7, according to the direction 0 motion applied. Continued motion of the shaft B w1ll then bring the second carrier G of the drum 0 into operation with its amociated carry-over sprocket H, and cause a two step movement to be imparted to the drum D, followed by successive two step movements which will be carried on as they accumulate first to the drum D then to the drum E, and finally to the shutter F, which also may be formed to constitute an indicator member.

With mechanism of this construction the direct driven drum 0 may be marked with fractional indications as shown developed at Figure 8, the drum D with unit indications, the drum E with tens indications, each as shown developed at Figure 9 and the shutter F with hundred indications, see Figure 2. The shutter is also formed with transverse apertures, one for each transverse strip of indications marked on the drums C, D and E. These transverse apertures are-arranged to form two groups, one group L through which ositive indications will be seen, and anot er group L through which negative indications will be seen, and through both groups zero indications will be seen. In arrangement, the

apertures of the group L extend from an edge coincident, or approximately so, with the upper edge of the window A and extend across the window downwardly therefrom, those of roup L extend from an edge coincident with the lower edge of the window A and extend across the window upwardly therefrom.

With these markings the mechanism in operation for positive values will exhibit at the window A indications as follows Movement. Shutter. Drum E. Drum D. Drum 0.

Blank 0 0 0 0 Blank Blank 0 0 34 Blank 0 0 36 Blank 0 o Blank 0 1 Blank Blank 0 1 Blank 0 1 Blank 0 1 Blank 0 2 Blank 9th Blank 0 2 and no on up to 1 9 0 1 For negative values from the zero position the indications will be as follows Movement. Shutter. Drum E. Drum D. Drum 0.

B ank 0 0 0 0 Blank Bank 0 0 B ank 0 0 Blank 0 0 Blank 0 1 Blank 1 e 0 M For distinguishing the ositive from the negative indications, mar 'ngs of difi'erent colour or character may be adopted.

Thus it will be recognized that in the zero position the shutter exhibits a blank, the drum E exhibits 0 0, the drum D, exhibits 0 0, and the drum C exhibits a blank. The first movement for either positive or negative indications causes motion to be imparted to the drum C, by direct drive corresponding to a indication, and motion to be impartedto the drum D, the drum E and shutter F, by transmitted drive through the carry-over gear corresponding to one step. This one step movement of the shutter taking the case for positive indications as shown at Figure 6, causes the group of apertures L to be removed from the window A and new portions of the group of apertures L to be brought beneath the window, simultaneously the second 0 on the drum E, the second 0 on the drum D, and the indication on the drum C are brought into osition beneath the window. The secon and third movements only affect drum C'as it asses through indications and The i durth movement affects drum C and drum D, drum C passes to a blank indication and a first stem motion in trans- ,4; indications adopted on drum C, the circumferential markin would embrace the value of one unit, w ereas if three carriers situated at equal intervals apart were provided the circumferential markings would embrace the value of three units. In the same manner the members, such as the drums D and E, may be rovided with more than one carrier G, whic with mechanism of the character described and gear suitably modified would, say, in the case of two carriers arranged diametrically bein provided on the drum D, necessitate markings indicating units embracing the value of two tens.

In the exalnple'illustrated at Figure 10, C designates a direct-driven disc, which is formed to constitute an indicator disc, D an indicator and F a shutter, each of disc form. In this view carry-over gear b which motion is transmitted to D and F is not shown, and it is thought that the operation of the mechanism in this form will be understood without further explanation.

I claim 2-- 1. Indicator apparatus comprising 1!. casing, a longitudinal window in the casing, carry-over ear, a driven member from which stepy-step motion is imparted by the carry-over gear to an indicator member, a shutter having transverse apertures through which and the window transverse strips of the indicator member may be viewed, the indicator member havin two such transverse strips, so construe and arranged that in one position of the parts a portion of each of the two transverse strips on the indicator member is exposed to view in longitudinal alignment through the transverse apertures in the shutter, and the carryover gear so arranged that when the parts are in that position it shall operate, by motion imparted to the driven member, to impart to the indicator member and to the shutter a one step movement simultaneously with the initial movement of the driven member in either a forward or backward sense according to the direction of motion im arted, whereb the shutter operates to hi e from view, in the longitudinal alignment aforesaid, the portion of one of the two transverse strips on the indicatormemher while leaving a portion of the other transverse strip on the indicator member exposed to view, markings on each. transverse strip of the indicator member comprising two similar indications in succession in 0 rating the gear driven member and the I each transverse strip, for the purposes se 5 utter, two transverse stri of numeral 10 forth. markings on the surface of 0 gear driven- 2. Indicator apparatus comprising 2. casmember, each of the markin consisting of 5 ing a longitudinal window in thecasing, a numerals arranged consecutively in duplidirect driven member, a gear driven memcate palrs, for the purposes set forth. ber, a shutter, two groups of transverse apertures in the shutter, carry-over gear for CHARLES DALRYMPLE MAOGILL 

